Fetal orbital and ocular biometry at different gestational ages

IntroductionDetermination of orbital and ocular growth patterns in fetal life is necessary for early diagnosis of facial malformation syndromes. We aim to establish the normative data for growth of different ocular and orbital parameters. These parameters may also correlate with fetal anthropometry.MethodsFifty normal fetuses at different gestational ages were studied for anthropometric, orbital and ocular growth. The parameters measured included weight, height, biparietal diameter, depth and width of the orbit, interorbital distance, transverse and vertical corneal diameters, axial and transverse diameters of the eyeball and diameter of the lens. Normative values were determined for orbital and ocular parameters in fetuses of 11–36 gestational weeks.ResultsThe orbital and the ocular parameters demonstrated significant positive correlation with age and biparietal diameter. However, the lens diameter did not show any significant correlation with either age or biparietal diameter. Among orbital parameters interorbital distance showed maximum correlation with biparietal diameter. The correlations of orbital and ocular parameters were better defined in males.ConclusionsThe gestational age specific normative data generated in this study may provide reference for comparing the growth of various orbital and ocular parameters and may aid in early diagnosis of fetal maldevelopment syndromes.     

The information content of Doppler ultrasound signals from the fetal heart

Knowledge of the content of Doppler ultrasound signals from the fetal heart is essential if the performance of fetal heart rate (FHR) monitors based upon this technology is to be improved. For this reason instrumentation was constructed to enable the simultaneous collection of Doppler audio signals and the transabdominal fetal ECG (for signal registration), with a total of 22 recordings being made with an average length of around 20 minutes. These data demonstrate the transient nature of the Doppler audio data with wide variations in the signal content observable on a beat-to-beat basis. Short-time Fourier analysis enabled the content of the Doppler signals to be linked to six cardiac events, four valve and two wall motions, with higher frequency components being associated with the latter. This differing frequency content together with information regarding the direction of movement that can be discerned from Doppler signals provided a potential means of discriminating between these six events (which are unlikely to all contribute to the Doppler signal within the same cardiac cycle). Analysis of 100 records showed that wall contractions generate the most prominent signals, with atrial contraction recognisable in all records and ventricular wall contraction in 95% (although its amplitude is only around 30% of that of the atrial signal). Valve motion, with amplitudes between 15 and 25% that of the atrial wall signal, were visible in 75% of records. These results suggest means by which the six events that contribute to the Doppler signal may be distinguished, providing information that should enable an improvement in the current performance of Doppler ultrasound-based FHR monitors.     

Recording and processing of fetal movements and sounds obtained with the Inpho inductive transducer

A recently developed transducer based on an inductive principle allows recording of fetal displacement signals on the maternal abdominal wall. The transducer is a relatively passive device, in contrast to commonly applied ultrasound transducers. This permits long-term observation of fetal movements and sounds. The bandwidth of the system is DC −200 Hz (±3dB), and signal-to-noise ratios of more than 96 dB have been measured in a laboratory setup, whereas in the practical situation a signal-to-noise ratio of 78 dB has been established. The transducer has been applied to study fetal respiratory sinus arrhythmia, which means that fetal breathing movements have to be extracted from the transducer's output. This proved possible by digital filtering of the displacement signal as detected by the transducer. The transducer has also been applied in a study where the signal-to-noise ratio of fetal heart sounds as a function of location of the fetus and position of the transducer on the maternal abdominal wall has been studied. It proved possible to adequately record fetal heart sounds for measurement of fetal heart rate. Also uterine activity could be recorded using the sensor's DC output.     

Detection of fetal breathing and cardiac movements and rhythms in ultrasonic Doppler signal recorded on the surface of the maternal abdomen

It is proposed to use information on the direction of reflector movement and extensive filtering in the detection of fetal breathing and cardiac movements in the ultrasonic Doppler signal recorded on the surface of the material abdomen. The method appears fairly insensitive to spurious signals and allows those of interest to be distinguished without any reference technique. A decision rule for breathing and cardiac rhythm detection, incorporating movement direction, amplitude, shape and periodicity criteria, is also proposed.     

Detection of fetal electrocardiogram signals using matched filters with adaptive normalisation

The authors discuss the application of matched filters to the detection of R-waves in fetal electrocardiogram (FECG) data, recorded during labour using a scalp electrode. When using the basic matched filter, one correlates a template representing the clean signal with the noisy signal. This method is optimal when the underlying noise is white in nature. However, it is known that false detection of R-waves can occur in the presence of extraneous peaks which have a similar shape to the fetal R-wave. It is proposed to switch between two different normalisations of the impulse response of the matched filter to alleviate this problem. When the signal-to-noise ratio is lower than a predetermined threshold, then normalisation to the geometric mean of the template and noisy data energies is carried out, otherwise only normalisation to the template energy is made. In the former case, the background noise and spikes that are larger than the underlying FECG are attenuated, hence increasing the probability of detection of the R-waves. In the latter case, noise which has a lower amplitude than the underlying R-wave, is reduced. The effectiveness of this method is demonstrated by application to scalp electrode data.     

胎儿窘迫157例分析

目的探讨胎儿窘迫对围产儿的影响.方法对2002年1月王2004年1月应用胎心率电子监护共2048例,作一回顾性分析.结果诊断胎儿窘迫至分娩时间越长,新生儿Apgar低分越多,有显著性差异.各种分娩方式之预后间无明显差异.314例胎儿窘迫中有72例发生新生儿窒息.结论胎心监护异常伴羊水粪染Ⅱ°～Ⅲ°为胎儿窘迫的可靠依据.应高度重视胎儿窘迫的危害性,加强预防,及时采取必要的分娩方式终止妊娠,改善国产儿预后.     

基层医院胎儿先天性心脏病超声筛查的价值

目的探讨在基层医院对胎儿严重先天性心脏病进行超声筛查的价值。方法对1754例胎儿进行八个心脏切面的检测。结果共检出严重先天性心脏病9例,并经证实,真阳性率100%。结论在基层医院开展胎儿严重心脏超声筛查可行,对优生优育有重要意义。     

Comprehensive fetal monitoring by microcomputer—A clinical approach

An inexpensive microcomputer has been devised to analyze fetal heart signals and fetal activity which were simultaneously recorded. Digital techniques were used to provide quantitative analysis of each of these inputs, and the interrelations among them. A parallel graphical presentation of those inputs was also provided.     

胎儿有核红细胞水平及其在发育异常胎儿的表达

目的检测18~38w胎儿血液有核红细胞水平,了解胎儿水肿、胎盘增厚、羊水极少等胎儿发育异常时有核红细胞(NRBO)的变化,为胎儿疾病的诊断、病因病理的分析和预后评估提供理论依据。方法应用B超引导下经母腹脐静脉穿刺术获取127例孕18~38w胎儿脐血(经胎血鉴定),快速推片、染色、计算每100个白细胞中含有核红细胞的个数,并进行分组统计。同时检测48例水肿、胎盘增厚、羊水极少等胎儿发育异常的有核红细胞,与同孕周正常胎儿比较。结果胎儿血有核红细胞:18~22w、23~26w、27~30w、31~34w、35~38w各孕周组分别为13.2±5.8,10.5±7.1,7.7±4.6,5.4±3.4,3.3±2(每100个白细胞中含有核红细胞的个数±SD),其水平随孕周增加而下降,统计学有显著差异,水肿胎儿、胎盘增厚、羊水极少者胎儿有核红细胞显著高于正常同孕周组,有统计学差异。结论胎儿血有核红细胞水平,可作为胎儿水肿、胎盘增厚、胎儿发育迟缓(SGR)并羊水极少等发育异常胎儿诊断与评估的参考指标。     

异常妊娠孕妇外周血中胎儿细胞的数量研究

目的研究异常妊娠孕妇外周血中胎儿有核红细胞的数量变化。方法富集孕妇外周血中胎儿有核红细胞后计数,再用PEP—PCR技术鉴别其来源。比较中孕期妊高征组、胎儿畸形组、死胎组与正常妊娠组孕妇外周血中胎儿有核红细胞的数量有无差异。结果3组异常妊娠样本中的胎儿有核红细胞的数量均明显高于正常妊娠组（P〈0．05）。3组异常妊娠组的胎儿有核红细胞数量之间无明显差异（P〉0．05）。结论发生妊高征、胎儿畸形与死胎的孕妇外周血中胎儿有核红细胞的数量异常升高,起一定的标志作用。     

Discovering a new part of the phenotypic spectrum of Coffin-Siris syndrome in a fetal cohort

PurposeGenome-wide sequencing is increasingly being performed during pregnancy to identify the genetic cause of congenital anomalies. The interpretation of prenatally identified variants can be challenging and is hampered by our often limited knowledge of prenatal phenotypes. To better delineate the prenatal phenotype of Coffin-Siris syndrome (CSS), we collected clinical data from patients with a prenatal phenotype and a pathogenic variant in one of the CSS-associated genes.MethodsClinical data was collected through an extensive web-based survey.ResultsWe included 44 patients with a variant in a CSS-associated gene and a prenatal phenotype; 9 of these patients have been reported before. Prenatal anomalies that were frequently observed in our cohort include hydrocephalus, agenesis of the corpus callosum, hypoplastic left heart syndrome, persistent left vena cava, diaphragmatic hernia, renal agenesis, and intrauterine growth restriction. Anal anomalies were frequently identified after birth in patients with ARID1A variants (6/14, 43%). Interestingly, pathogenic ARID1A variants were much more frequently identified in the current prenatal cohort (16/44, 36%) than in postnatal CSS cohorts (5%-9%).ConclusionOur data shed new light on the prenatal phenotype of patients with pathogenic variants in CSS genes.     

用孕妇血中胎儿物质产前诊断胎儿染色体异常研究进展

利用孕妇血中胎儿细胞、游离胎儿DNA/RNA对胎儿染色体病进行诊断一直是产前诊断领域研究热点.在研究的早期阶段,以胎儿有核红细胞作为产前诊断目标细胞,对其进行了大量研究.各种细胞分离技术被用于富集胎儿的有核红细胞.荧光原位杂交技术被用于分析浓缩的有核红细胞.但终因孕妇血中胎儿的有核红细胞含量极低,分离浓缩困难而没能用于临床.近年来研究人员发现,在母体血浆中存在胎儿核酸物质,利用母体血浆中胎儿DNA/RNA进行无创性产前诊断研究成为了另一个研究热点.与胎儿有核红细胞相比,在孕妇血中胎儿的核酸物质含量丰富.应用胎儿核酸诊断胎儿染色体非整倍体已成为可能.随着新的分子生物学技术的不断发展,这种无创性产前诊断技术有望应用于临床.本文对近年来用孕妇血中胎儿细胞和游离胎儿DNA、RNA无创性产前监测胎儿染色体非整倍体的研究进行综述.     

分组筛查排除胎监无负荷试验假无反应型的对比研究

目的提高胎心电子监护无应激试验(NST)的准确性,对NST假无反应型予以正确筛查.方法采用振动声刺激、吸氧、体位改变3种方法对120例NST无反应型进行分组筛查研究,仍为NST无反应型者继续在B超下进行NST监测.结果 NST假无反应型的发生率较高,约为95%.3种方法筛查NST假无反应型的效果存在显著差异,以振动声刺激组效果最佳,NST转为阳性率达83.33%(P＜0.05).结论孕期实际存在胎儿宫内缺氧及胎盘功能减退的极少,振动声刺激试验可作为筛查NST假无应型的首选方法.     

胎儿生长受限的早期诊治

胎儿生长受限（FGR）不仅使胎儿宫内发育落后,而且会影响到胎儿出生后的发育及生活质量。但其病因及生理机制未明,孕早中期对FGR的诊断困难,常在孕晚期才能诊断。因此如何早期预测FGR并对其进行诊疗,以获得较好的母婴结局一直是国内外研究的热点。现将对FGR早期诊断的方法及治疗进展进行综述。     

The psychophysiology of the maternal-fetal relationship

The enigmatic quality of the maternal-fetal relationship has been extolled throughout history with little empirical support. We apply time series analysis to data for 137 maternal-fetal pairs collected at 20, 24, 28, 32, 36, and 38 weeks gestation. Maternal heart rate and skin conductance data were digitized in tandem with fetal heart rate and motor activity. No temporal relations between fetal heart rate and either maternal variable were found, although averaged maternal and fetal heart rates were correlated from 32 weeks. Consistent temporal associations between fetal movement and maternal heart rate and skin conductance were detected. Fetal movement stimulated rises in each parameter, peaking at 2 and 3 s, respectively. Associations did not change over gestation, were unaffected by a maternal stressor, and showed within-pair stability. The bidirectional nature of the maternal-fetal relationship is considered.     

胎儿心率变异性的近似熵分析在胎儿窘迫诊断中的应用

介绍一种近似熵分析方法,并将其应用于胎心率变异性的研究中,探讨近似熵分析结果与临床胎儿窘迫的相关性。对67例次胎心电子监护(CTG)结果经胎心率变异性的近似熵分析及时域分析。新生儿出生后记录Apgar评分,取脐动脉血行血气分析。结果显示胎心率变异性的近似熵值ApEn与脐血血气分析指标pH、Pco2、Po2、HCO3-、ABE、SO2及新生儿评分Apgar有显著相关性(r=0.51、-0.29、0.49、0.29、0.45、0.56、0.28,P值均<0.05);酸中毒组(pH≤7.2)胎心率变异性的ApEn值显著低于正常组(pH>7.2)(P<0.01),而常规时域分析指标平均胎心率(BHR)、胎心率标准差(SD)、胎心率变异系数(CV)则无显著性差别。提示胎心率变异性的近似熵值是一较敏感的反映胎儿缺氧酸中毒的指标,近似熵分析方法可为胎儿窘迫早期诊断的准确性提供新的思路。     

Recording fetal breathing movements with a passive transducer based on an inductive principle

A new transducer has been developed, based on an inductive principle, for recording fetal movements and sounds. The compliance of this transducer, the INductive PHOno-sensor (INPHO), can be matched to that of the maternal abdomen to provide an optimal transfer of displacement between maternal abdomen and transducer. In this manner it is possible to detect fetal breathing movements by digital filtering of the INPHO signal in a frequency band between 0·5 and 2·0 Hz. Singular breathing movements can be detected and this was verified by real time ultrasound imaging. The INPHO transducer shows a flat (±1·5 dB) frequency response between 0·2 and 200 Hz. The signal-to-noise ratio of the transducer system is better than 95 dB, and enables very weak movements and sounds to be detected. Spectral analysis of the processed signal shows that modulation of fetal breathing by maternal breathing takes place. The measuring setup allows for the quantitative assessment of fetal respiratory sinus arrythymia.